Sinai Plate Research Articles

Kinematics of the Kahramanmaraş triple junction and of Cyprus: evidence of shear partitioning

Triple junctions involving convergent plate boundaries extend beyond local implications, which is crucial for studying the geology of convergent plate boundary zones. However, kinematic models overlook Cyprus-Anatolia motion due to limited geodetic constraints. Our study area comprises Cyprus, southern Turkey, and the Levant coast, focusing on the Kahramanmaraş triple junction, where a destructive earthquake sequence occurred on February 6, 2023. We present precise positioning data merged with published velocities, constructing an up-to-date velocity field for the interseismic period. Employing two kinematic approaches, we analyze its tectonic implications. In Cyprus, we find the relative motion of Africa (Sinai Plate) and Anatolia is partitioned between convergence in the Cyprus subduction, with a rate of 3.5–6.2 mm/yr, progressively decreasing from west to east and left-lateral transpressive Kyrenia fault, situated along the northern coast of Cyprus, with rate 3.3–4.2 mm/yr. The relative strike-slip motion between Arabia and Anatolia is partitioned between the East Anatolian Fault (slip rates 5.2–6.2 mm/yr) and some secondary faults such as Çardak and Malatya faults (slip rates 2.0–1.7 mm/yr respectively) and causes distributed deformation for a 50–60 km wide region. The largest second invariant strain rate tensors from the continuum kinematic model also coincide with the same region, the East Anatolian shear zone. A shear partitioning system exists around the Kahramanmaraş triple junction, from Cyprus to southeast Turkey. The Levant Fault has a 3.5–4.7 mm/yr left-lateral slip rate, decreasing northward as part of it is transferred to offshore faults. Strain rates appear relatively small in the Taurus range and Adana/Cilicia basin, transitioning from extensional/transtensional to compressional from east to west.

Reconstructing the slip velocities of the 1202 and 1759 CE earthquakes based on faulted archaeological structures at Tell Ateret, Dead Sea Fault

Archaeological structures built across active faults and ruptured by earthquakes have been used as markers to measure the amount of displacement caused by ground motion and thus to estimate the magnitude of ancient earthquakes. The example used in this study is the Crusader fortress at Tel Ateret (Vadum Iacob) in the Jordan Gorge, north of the Sea of Galilee, a site which has been ruptured repeatedly since the Iron Age. We use detailed laser scans and discrete element models of the fortification walls to deduce the slip velocity during the earthquake. Further, we test whether the in-situ observed deformation pattern of the walls allows quantification of the amount both sides of the fault moved and whether post-seismic creep contributed to total displacement. The dynamic simulation of the reaction of the fortification wall to a variety of earthquake scenarios supports the hypothesis that the wall was ruptured by two earthquakes in 1202 and 1759 CE. For the first time, we can estimate the slip velocity during the earthquakes to 3 and 1 m/s for the two events, attribute the main motion to the Arabian plate with a mostly locked Sinai plate, and exclude significant creep contribution to the observed displacements of 1.25 and 0.5 m, respectively. Considering a minimum long-term slip rate at the site of 2.6 mm/year, there is a deficit of at least 1.6 m slip corresponding to a potential future magnitude 7.5 earthquake; if we assume ~5 mm/year geodetic rate, the deficit is even larger.

Gulfs of Suez and Aqaba: New insights from recent satellite-marine potential field data

Previous models and interpretations of crustal geometry and the nature of the crust under the Gulfs of Suez and Aqaba have generally been based on a local or small scale and have been limited due to a lack of data. The few studies that present larger scale crustal and uppermost mantle structure were dependent on one type of data with no consideration of other geological and/or geophysical features. Satellite-marine potential field data provide for the first time a full coverage dataset of the Gulfs of Suez and Aqaba as well as the Sinai area at the same scale which allows for a better understanding of crustal domains and geometry and the interplay between tectonic events. To that end, our forward models of magnetic and gravity data constrained by seismic data and available geological information in this area suggest that the crustal domains in the Gulf of Aqaba are more complicated than those in the Gulf of Suez. Our result supports continental rifting under most of the Gulf of Suez and a combination of transitional and continental crusts under the Gulf of Aqaba. Yet, there is no evidence of oceanic segment development in these gulfs. Regardless of oceanic or transitional crust, the models support a link between the Arabia and Sinai plates at the central Gulf of Aqaba. The data also support that Red Sea tectonism has no connection to or influence on both gulfs. The result suggests a continuation of lithological elements from land into the eastern part of the Gulf of Suez. Our synthesis and interpretations may play an important role in the reassessment of the tectonic history and extension of this important rift system.

Eastern Mediterranean: Combined geological–geophysical zonation and paleogeodynamics of the Mesozoic and Cenozoic structural-sedimentation stages

The eastern Mediterranean, in the Neo-Tethyan collision zone, consists mainly of the Mesozoic terrane belt and the adjoining oceanic crust complex of the northern part of the Sinai plate. The recent discovery of large hydrocarbon deposits has attracted considerable attention to this region. Combined analysis of gravity, magnetic, paleomagnetic, tectonic, structural and paleogeographical data sheds light on the tectonic evolution of this region. The Kiama paleomagnetic zone of inverse polarity, discovered in the oceanic crust of the eastern Mediterranean suggests transport along transform faults from the eastern part of the Tethys Ocean. The discrepancy between the terrane belt and the Nubian–Arabian foreland, oceanic crust, and terrane belt testify to the allochthonous nature of the eastern Mediterranean. For the first time, formation-paleogeographical maps of structural stages from the Triassic to the Neogene–Quaternary have been compiled. The integrated tectono-geophysical and paleogeographical specifics of deep zonation call for a reevaluation of regional criteria for oil and gas exploration.

Newly developed paleomagnetic map of the EasternmostMediterranean joined with tectono-structural analysis unmaskgeodynamic history of this region

AbstractComprehensive magnetic-paleomagnetic analysisof physical-geological models developed for the EasternmostMediterranean (northern part of the Sinai plate)accompanied by gravity and seismic data examination enabledthe detection of a zone of inverse magnetizationof submeridional strike with a total volume exceeding120,000 km3. Such a large zone must correspond to theprolonged period of inverse polarity in the Earth’s magneticfield history. We suggest that this inversely magnetizedthick block of the Earth’s crust corresponds tothe known Kiama hyperzone. A paleomagnetic map constructedon the basis of abovementioned geophysical dataanalysis combined with detailed examination of structural,radiometric, petrological, facial, paleogeographicaland some other data indicates that to the west ofthe Kiama zone is situated the Jalal zone, and to theeast – Illawarra, Omolon and Gissar zones. Discovery ofthe Kiama paleomagnetic zone combined with tectonogeodynamicalanalysis and paleobiographical data examinationindicates that the Earth’s oceanic crust blocks mayhave been shifted by transform faults from the eastern partof the Tethys Ocean to their modern position in the EasternmostMediterranean. Analysis of potential geophysicalfields and seismological maps integrated with tectonostructuralexamination show the isolation of the northernpart of Sinai plate from other terranes. For the first timeformation-paleogeographical maps of Triassic and Jurassicfor the Easternmost Mediterranean have been compiledand their tectono-geodynamical explanation hasbeen given. The obtained data create a basis for reconsideringtectonic zonation, paleogeodynamical reconstructionsand searching for economic deposits in this region.

Kinematic study at the junction of the East Anatolian fault and the Dead Sea fault from GPS measurements

The Hatay Triple Junction (HTJ) is a tectonically complex area located at the intersection between the left-lateral East Anatolian fault (EAF), the Cyprus subduction arc and the left-lateral Dead Sea fault (DSF) which is a transform boundary between the Arabian and Sinai plates as they converge toward Eurasia. Previous GPS studies indicate a left-lateral strike-slip rate across the DSF varying from 5mm/yr (along the southern part) to 2mm/yr (along the northern part) (Alchalbi et al., 2010; Gomez et al., 2007; Le Béon et al., 2008; Mahmoud et al., 2005; Al-Tarazi et al., 2011). In contrast, the EAF has a roughly constant velocity along strike estimated at 9.7+0.9mm/yr (Reilinger et al., 2006). The HTJ contains several well-identified active fault segments (DSF, EAF, Osmaniye fault, Karasu fault, Latakia fault, Jisr-al-shuggur fault, Idleb fault and Afrin fault) (Meghraoui et al., 2011), the fault-slip rates for which are poorly constrained.In order to constrain better the slip rate on faults, we established a network of 57 GPS sites in NW Syria and in SE Turkey. The first campaign was carried out in September 2009; a second took place in September and November 2010 and a third (only in Turkey) in September 2011. Although the velocity field vectors computed from the 2009, 2010 and 2011 measurements appear consistent with other local studies, the results are hampered by large uncertainties due to the short observation period. However, preliminary interpretations are consistent with decreasing velocity along the DSF from south to north reported previously.

Seismic depth-domain stratigraphic classification of the Golan Heights, central Dead Sea Fault

A set of twenty five 2-D seismic profiles acquired over the Golan Heights basaltic plateau, central Dead Sea Fault segment, was processed and analyzed in the depth domain. The data were processed by the Pre-Stack Depth Migration techniques and, despite the thick basaltic layer entirely covering the plateau, shows surprisingly good quality. The study presents stratigraphic identification of eleven seismic markers recognized on the output depth-domain sections and their correlation with the adjacent Syrian, Jordanian and Israeli stratigraphic columns. Based on this regional correlation, the deep-seated structure and stratigraphic column underlying the extensive basaltic cover are addressed through structural mapping and isopach calculations, as well as through compilation of regional geological cross-sections. Results of the depth-domain seismic interpretation suggest that the Golan Heights covers a structural depression in which more than 8500 m of Late Proterozoic to Neogene sedimentary succession has accumulated, amid the Jordanian Highlands and the Mt. Hermon Anticline. The Infracambrian–Paleozoic succession attains a thickness of 3000–3500 m, while as much as 1500 m of this figure is attributed to the Late Proterozoic Saramuj Formation. The Mesozoic succession, outlined by the significant northward and north-western thickening of the Triassic and Jurassic successions, attains a cumulative thickness of 5 km in the Northern Golan. The Senonian–Cenozoic succession outlines the syncline nature of the Golan Plateau, attaining a thickness of 1.5–2 km at the central parts of the plateau. The estimated thickness of the Plio–Pleistocene basalt flows that cover the study area locally exceeds 1000 m. Two fault strands of the Dead Sea Fault System are recognized in the subsurface of the plateau: the Sheikh-Ali and Shamir Faults. The strands are interpreted beneath the basalt cover, extending into the plateau at a considerable distance from their surface expression next to the Arabian–Sinai plate boundary frontier, exhibiting various styles of deformation.

Tectonic-Geophysical Mapping of Israel and the Eastern Mediterranean: Implications for Hydrocarbon Prospecting

The eastern Mediterranean is a tectonically complex region evolving in the long term located in the midst of the progressive Afro-Eurasian collision. Despite years of investigation, its geological-geophysical structure is not completely known. At the same time, the recent discovery of large gas deposits has attracted the attention of many researchers to this region. For instance, the latest U. S. Geological Survey estimates using conventional assessment methodology suggest that there are on the order of 1.7 billion barrels of recoverable oil and more than 4 trillion m3 of recoverable gas in the Levant Basin [1]. This highlights the need for analysis of the paleogeographical conditions that can yield deep paleotectonic criteria for oil and gas discovery in this region. For this purpose, isopach maps of the Middle-Upper Jurassic and Lower Cretaceous were generated from detailed examinations of numerous well sections and the most significant outcroppings in the eastern Mediterranean. The maps confirm an earlier model of continental accretion [2]. In particular, abrupt changes in the trend and thickness of the Early Mesozoic formations coincide with the terrane boundaries. These compiled isopach maps also pinpoint significant distinctions between the Arabian and Sinai plates on the one hand and the Syrian arc on the other. A new tectonic map of the eastern Mediterranean is presented that first of all integrates geophysical satellite-derived gravity and airborne magnetic fields, as well as tectonic-structural, paleogeographical and facial analyses. The results have clear implications for hydrocarbon prospecting in this region.

What triggered the early-to-mid Pleistocene tectonic transition across the entire eastern Mediterranean?

Subduction plays a fundamental role in plate tectonics and when interrupted it may trigger a series of geodynamic and sedimentary responses. Synchronous structural modifications recorded across the entire eastern Mediterranean region are dated to a relatively short period — early-to-mid Pleistocene. These deformations are documented within plates (e.g., Arabian, Sinai and African plates), along plate boundaries (e.g., Dead Sea and North Anatolian faults and Cyprus Arc), and in the Mediterranean basin. During the same period the northward subduction of the Sinai plate was interrupted when the Eratosthenes Seamount–Cyprus Arc collision initiated. Subduction–collision processes of the eastern Mediterranean serve as a unique modern analogue for similar settings worldwide. Understanding their association with accompanying neo-tectonic processes is therefore predominantly important. By fostering a detailed and comprehensive approach this research provides a coherent tectonic picture for the eastern Mediterranean early-to-mid Pleistocene tectonic transition in order to explore its triggering mechanisms. Since the Neogene convergence across the eastern Mediterranean was accompanied by Eurasian indentation by Arabia northward motion, westwards Anatolia escape and southwards Aegean propagation. This semi counterclockwise plate motion was temporarily interrupted by the incipient Seamount–Arc collision which is suggested here as a trigger of the early-to-mid Pleistocene tectonic transition.

Crustal deformation in northwestern Arabia from GPS measurements in Syria: Slow slip rate along the northern Dead Sea Fault

SUMMARY New Global Positioning System (GPS) measurements in NW Syria provide the first direct observations of near-field deformation associated with the northern Dead Sea fault system (DSFS) and demonstrate that the kinematics of the northern section of this transform plate boundary between the Arabian and Sinai plates deviate significantly from plate model predictions. Velocity estimates based on GPS survey campaigns in 2000, 2007 and 2008, demonstrate left-lateral shear along the northern DSFS with 1σ uncertainties less than 0.7 mm yr−1. These velocities are consistent with an elastic dislocation model with a slip rate of 1.8–3.3 mm yr−1 and a locking depth of 5–16 km. This geodetically determined slip rate is about half of that reported farther south along the central section (Lebanese restraining bend) and the southern section (Jordan Valley and Wadi Araba) of the transform and consequently requires some deformation to occur away from the transform along other geological structures. The factor of two difference in slip rates along the transform is also consistent with differing estimates of total fault slip that have occurred since the mid Miocene: 20–25 km along the northern DSFS (in NW Syria) versus about 45 km along the southern DSFS segment. Some of the strain deficit may be accommodated by north–south shortening within the southwestern segment of the Palmyride fold belt of central Syria. Additionally, a distinct change in velocity occurs within the Sinai plate itself. These new GPS measurements, when viewed alongside the palaeoseismic record and the modest level of present-day seismicity, suggest that the reported estimates of recurrence time of large earthquakes (M > 7) along the northern section of the DSFS may be underestimated owing to temporal clustering of such large historical earthquakes. Hence, a revised estimate of the earthquake hazard may be needed for NW Syria.

Subduction, collision and initiation of hominin dispersal

Subduction is the main driving force of plate tectonics controlling the physiography of the Earth. The northward subduction of the Sinai plate was interrupted during the Early Pleistocene when the Eratosthenes Seamount began to collide with the Cyprian arc. A series of synchronous structural deformations was triggered across the entire eastern Mediterranean, and local topography was drastically accentuation along the Levantine corridor – one of the main pathways of hominin dispersal out of Africa. However, the choice of this preferred pathway and timing of dispersal has not been resolved. Though causes for dispersal out of Africa are in debate, we show that the transition from subduction to collision in the eastern Mediterranean set the route.

Seismotectonics of the Cyprian Arc

SUMMARY The Cyprian Arc forms the plate boundary between the Anatolian plate in the north and the Nubian and Sinai plates in the south. We examine the tectonic setting and seismic activity along the arc in light of new geodetic studies indicating relative NE‐SW plate motions across the arc. The first-order tectonic variations are determined by the arc’s geometry. The eastern arc, oriented subparallel to relative motion, is dominated by transcurrent tectonism. The western arc is oriented almost normal to relative plate motion and is subjected to convergent processes. Variations in the level and depth of seismic activity along the western arc suggest that the northwestern section of the arc represents a subduction boundary, whereas the southeastern section represents a collision boundary. The two tectonic domains of the western arc are separated by a NE‐SW trending tear fault, which produces large earthquakes, such as the MW = 6.8, 1996 Paphos earthquake. We compare the geometrically similar Cyprian and Hellenic Arcs and find significant differences in the rate, direction and type of convergence across the two arcs. The Hellenic Arc is subjected mainly to subduction, whereas the shorter Cyprian Arc is subjected to subduction, collision and transcurrent tectonic processes.

The structure of the Dead Sea basin

The Dead Sea basin is located along the left-lateral transform boundary between the Arabian and Sinai plates. Its structure and history are known from surface geology, drilling, seismic reflection and other geophysical data. The basin comprises a large pull-apart, almost 150 km long and mostly 8–10 km wide, which is flanked by a few kilometres wide zones of normal faulting. The basin formed at about 15 Ma or earlier, close to the beginning of the transform motion, and it reached about half its present length before the end of the Miocene. A strong negative gravity anomaly records a thick sediment basin fill: > 5 km under half its length, reaching a maximum of ≥ 10 km. The fill includes a few km of salt (ca. 6-4 Ma) which forms several diapirs. At any one time large parts of the basin subsided simultaneously, but the site of fastest subsidence seems to have shifted northward. Sedimentation rates reached at least hundreds of metres per million years or more in the Miocene, and ≥ 1 km/Myr in later periods. The basin structure is dominated by longitudinal faults: intrabasinal faults which delimit the pull-apart and which are the extensions of the major strike-slip faults north and south of the basin, and normal faults which extend along the basin margins. The latter faults express a small component of extension across the basin, whereas the pull-apart resulted from the much larger lateral motion along the basin. In addition, transverse faults divide the pull-apart into several segments with somewhat different histories. The pull-apart grew by becoming longer parallel to the transform motion. At shallow levels this was probably achieved by normal slip on transverse listric faults while the fill between them was little deformed. The crust under the basin was stretched and thinned during basin lengthening, which caused its subsidence. Basin formation was accompanied by uplifting of its flanks by ≥ 1 km. Sparse igneous activity occurred along the basin and its flanks. Its presence suggests a thermal anomaly in the lower lithosphere beneath the basin and adjacent parts of the transform.

Diverse origin of modern dolomite in the Levant

The Dead-Sea transform in the Levant is a plate boundary that separates the Arabian from the Sinai plates. Along this transform modern dolomite occurs insabkhas, sea-marginal ponds, deep-sea settings, and non-marine saline springs. The non-marine dolomite from saline springs is of hydrothermal origin. Thesabkha and deep-sea dolomite are detrital and recycled from Cretaceous bedrock. The dolomite in sea-marginal ponds owes its origin to salinity-elevated seawaters and is an evaporite mineral. On the Sinai plate dolomite formed through the methane pathway, and west of the transform dolomite formed in caves from fresh-water effluent. Hence in one single geologic province modern dolomite is of multiple origins

A. M. Quennell Father of Transform Faults and Poles of Rotation?

In the 1940s and 1950s, A. M. Quennell (1906–1985) was using, in a very practical way, many of the concepts of plate tectonics which were to become so important in the 1960s and 1970s. He spent most of his working life in the Middle East and Africa and made the Dead Sea Rift his special study. In his first major publication on the geology and mineral resources of former Trans‐Jordan in 1951, he came down firmly in favor of the views originally proposed by Lartet [1869] that the Dead Sea Rift is due to shear and the Red Sea to drift, the shear zone being the boundary between the “Palestine block” (Sinai plate) and the “Arabia block” (Arabian plate).

The tectonic style of the southern Arava Rift margins, Israel: alternating stress fields in wrench-rifting processes

Abstract The Arava Rift segment of the Dead Sea Transform contains juxtaposed transtensional and transpressional tectonic elements. This structural pattern is related to the disposition of individual, en-echelon faults which accommodate the horizontal slip with respect to the regional stress field. A detailed study of mesostructural elements across two transpressional structures at the western margins of the Arava Rift has established a tectonic sequence and subsequent adjustment of the concurrent drainage systems. The studied structures are the Shizafon Disturbance, an array of narrow asymmetric monoclinal and anticlinal folds and the Ya'alon Graben, a left-lateral, branching wrench fault, with some downfaulted internal blocks. Slickensides on small faults, small-scale rhomb-grabens, veins with secondary mineralization and tectonic stylolites indicate that during an early compressional phase (Miocene-Lower Pliocene) the main horizontal compressional component ( σ 1 ) trended NW at the Shizafon Disturbance and NW to NNW at the Ya'alon Graben. Normal faulting commenced during the Middle Pliocene and formed antithetic blocks along the rift margins. Similarly alternating stress fields, whereby compression was succeeded by extension are recorded also several hundred kilometres further north along the transform margins. The extensive distribution of coeval events along the eastern Sinai plate margin calls for a regional stress field, most probably a change in the rotation pole of the plates bordering upon the Dead Sea Transform, of the sort implied by Garfunkel (1981). Due to the thin sedimentary cover (

Structural framework of the Gulf of Elat (AQABA), Northern Red Sea

The Gulf of Elat (Aqaba) occupies the southern part of the Dead Sea rift. The rift is considered to be a plate boundary of the transform type (partially leaky) which connects seafloor spreading in the Red Sea with the Sagros‐Taurus zone of continental collision. The deep water in the Gulf of Elat, up to 1850 m, provides a rare opportunity to examine the process of continental rifting by marine geophysical techniques. The bathymetry alone provides much information about fault patterns in this area. The fragmentation of the once continuous Arabian‐African platform is a complicated process. It shapes the structure of the gulf which has developed through continuing tectonism, primarily consisting of faulting. Recent geophysical and geological studies of the Gulf of Elat including bathymetry, bottom photographs, continuous seismic profiles, seismic refraction, gravity, magnetics, heat flow, and coring provide new information about the shallow and deep crustal structure of this important segment of the world rift system. The shallow structure of the gulf is dominated by three elongated en echelon basins, which strike N20°–25°E. Undulations in the floors of the basins produce several distinct deeps. These basins are interpreted as pullaparts. The new data from the gulf suggest that classical models for the formation of these structures should be modified. Only one of the longitudinal faults of each depression is a strike‐slip fault, while the other is predominantly a normal fault. The situation with the other two sides of the basin which are supposed to be composed of normal faults may also be more complex than previously thought. At least in one case, one such boundary is composed of a strike‐slip fault while the other has no significant fault. Crustal models of the Gulf of Elat based on gravity data indicate that the basins are rather shallow and do not extend into the lower crust. The fill of the basins extends to about 5 km below the seafloor in. the northern and southern basins and less in the central basin. Most significant magnetic anomalies in the Gulf of Elat extend from land into the sea. None of them, however, extends from one coast to another across the gulf. This supports the geological evidence for a shear between the Arabia and Sinai plates. The magnetic field over the southern third of the gulf is rather smooth and markedly different from that of the other parts. The nature of the magnetics, the crustal structure of the western margin, and the heat flow values indicate a thinner crust and different tectonic processes in the southern part of the gulf. Overall, it seems that within the southern Gulf of Elat a transition occurs between crustal spreading that takes place in the Red Sea to a rifting without spreading that takes place along the Dead Sea transform. Spreading activity propagates from south to north. The most active place is the central basin which is being propagated northward into the shallow northern basin.

The structure and tectonic setting of the levant continental margin, Eastern Mediterranean

The continental slope and rise of a segment of the Levant continental margin were investigated using continuous seismic profiling. The relatively small distances between the profiles and the accurate navigation make it possible to study small-scale variations in the structure and physical character of the stratigraphic sequence on the continental margin. Several prominent reflectors were identified through the entire area and their structure was mapped. Tectonic elements observed in this area consist of structures formed by compressional processes, and normal faults mainly along the continental slope. At the bottom of the slope a diapiric complex lies in a belt parallel to the slope, and in the Levant Basin a large diapiric field with smaller diapirs was mapped. A new conceptual model for the tectonic development of the Levant continental margin is described. The main idea is that the faulting along the continental slope is the expression of the two types of interaction at the northern boundary of the Sinai plate, with the Cyprian arc on one side, and with the Taurus Mountains in Turkey on the other.